Various energy-absorbing members formed using a fiber reinforced resin, for example, a carbon fiber reinforced resin, are known. For example, JP-HEI 6-300067 and JP-HEI 6-307477 disclose an energy-absorbing member which can smoothly perform a breakage of a member for energy absorption by a specified layered structure of a plurality of fiber reinforced resin layers. Further, JP-HEI 11-280815 discloses an energy-absorbing body which can stabilize a load at the time of a member collapse and avoid an early collapse by, with respect to a plurality of fiber reinforced resin layers to be layered, controlling a ratio of a thickness of the layered portion to a number of layers in a specified range.
In any of such conventional technologies, although a plurality of fiber reinforced resin layers having different properties are layered at a predetermined formation or order, as the fiber reinforced resin layers to be layered, ones having substantially a same size or a same shape are used. Therefore, if the entire shape of the entire size of an energy-absorbing member to be made is decided, an energy quantity capable of being absorbed is within a certain limited range, and when it is required to absorb an energy quantity greatly out of the range, the design frequently becomes difficult.
In practice, however, for example, when an energy-absorbing member being attached to a vehicle front portion is designed, since an energy quantity to be absorbed at the time of collision greatly varies depending upon the weight of a vehicle body attached to the energy-absorbing member, if the kind of the vehicle changes, in accordance with the change it becomes necessary to newly design it each time.
Accordingly, it could be helpful to provide an energy-absorbing member capable of easily adjusting and setting an optimum energy absorption quantity in accordance with a target value without greatly changing an outward shape even when the target value of an energy quantity to be absorbed is required to be changed.